Railroad cars are widely used in the United States and other countries to transport vehicles such as automobiles and trucks from manufacturing plants to distribution centers. Such railroad cars are referred to in the trade as auto rack cars.
The railroad cars include a floor and a pair of side walls which support at least one, and usually two, elevated decks. Additionally, a roof is generally included to protect the vehicles against damage. The floor and each deck carry lined-up vehicles.
It is customary to load, and for railroads to move, a number of such cars in groups hitched together end-to-end and, after arrival at a distribution center, for the group of cars to be unloaded simultaneously. When a group of cars is loaded simultaneously, they enter at one end and are driven forward as far as possible to a tie down position on one of the cars. This is called circus loading. To make such loading possible the distance between adjoining car ends must be spanned by removable bridge plates at the car floor level and at each deck level. The bridge plates support the vehicle wheels as the vehicles roll from one railroad car to the next.
Vehicles are unloaded from the group of railroad cars in a similar manner, referred to as circus unloading. Vehicles are driven forward from one car to the next over bridge plates and ultimately down ramps, at the forward end of the front car, to the ground.
Stoller et al U.S. Pat. No. 4,437,410 discloses an auto rack railroad car with a closure at each end to prevent vandalism and thievery. Each closure comprises two door assemblies which move horizontally to open and close the car end. The door assemblies are movably supported by a horizontal support member mounted on the front end or edge of the uppermost of two elevated decks. Mounted on the top of both decks, adjacent the front end, is a bridge plate attaching means which constitutes a ridge over which vehicles must be driven in loading and unloading the cars. Because there is very little clearance between the vehicle roof tops and the railroad car roof top or a deck, the ridge causes vehicles to bump and spring higher. This causes the vehicle roofs to hit the railroad car roof or deck and damage the automobile with significant economic loss. There is thus a need for alternative structural arrangements which permit removable attachment of bridge plates to railroad cars with elimination of the present described bump-inducing ridges.